Loop lock stitch shoe sewing machines



Oct. 16, 1962 c. KNoTT LOOP LOCK STITCH SHOE SEWING MACHINES 15 Sheets-Sheet 1 Filed Aug. 5, 1959 .1 u 4 'il I. il-2.5%@

Inventor:

Clyde L Kno Oct. 16, 1962 C, L, KNQTT 3,058,435

LOOP LOCK STITCH SHOE SEWING MACHINES Filed Aug. 5, 1959 13 Sheets-Sheet 2 Ik gf" d s l i* limlttwn.

OCL 16, 1952 c. l.. KNOTT 3,058,435

Loop Loox STITCH sHoE SEWING MACHINES Filed Aug. 5, 1959 l5 ShBeCS-Sheet 3 Oct. 16, 1962 c. L. KNO-r1' K LOOP LOCK STITCH SHOE SEWING MACHINES 15 Sheets-Sheet 4 Filed Aug. 5, 1959 Oct. 16, 1962 c. L. KNoTT Loop Locx STITCH sHoE SEWING MACHINES 13 Sheets-Sheet 5 Filed Aug. 5, 1959 Oct. 16, 1962 c. L. KNoTT Loop Loox vSTITCH sEoE SEWING MACHINES 15 Sheets-Sheet 6 Filed Aug. 5. 1959 Oct. 16, 1962 c. KNoTT I.oo1D Loox sIIIcH sHoE SEWING MACHINES 15 Sheets-Sheet '7 Filed Aug. 5, 1959 Oct. 16, 1962 c. l.. KNo'r-r LOOP LOCK STITCH SHOE SEWING MACHINES 11.5 Sheets-Sheet 8 Filed Aug. 5, 1959 Oct. 16, 1962 c. L. KNOTT Loor LOCK STITCH sHoE SEWING MACHINES 13 Sheets-Sheet 9 Filed Aug. 5, 1959 Oct. 16, 1962 c. KNoTT 3,058,435

LOOP LOCK STITCH SHOE SEWING MACHINES Filed Aug. 5, 1959 13 Sheets-Sheet 10 Oct. 16, 1962 c. KNoTT 3,058,435

LOOP LOCK STITCH SHOE SEWING MACHINES Filed Aug. 5, 1959 13 Sheets-Sheet 11 gleuf, I f 332 la QW @L f/czm Cen er' Supper- Oct. 16, 1962 c. L. KNoTT LOOP LOCK STITCH SHOE SEWING MACHINES Filed Aug. 5, 1959 F I .Pos/WON of @MMP 15 Sheets-Sheet 12 u//f/zdrau/s' and need/e enters wo rk Sgyeeze l Oct. 16, 1962 Filed Aug. 5, 1959 C. L. KNOTT LOOP LOCK STITCH SHOE SEWING MACHINES 15 Sheets-Sheet 13 @ie-Upg Fear- [ack Sei " alnf ack 3,658,435 L? LGCK STITCH SHE SEWWG MACS Clyde L. Knott, Beverly, Mass., assigner to United Shoe Machinery Corporation, Flemington, NJ., a corporation of New .lersey Filed Aug. S, 1959, Ser. No. 831,735 14 Claims. (Ci. i12-32) The present invention relates to loop lock stitch shoe outseam sewing machines of the type disclosed in United States Letters Patent No. 2,877,725, granted March 17, 1959, and an application for United States Letters Patent, Serial No. 750,392, led Iuly 23, 1958, both in the name of Joseph R. Ioannilli, and more particularly to improvements in stitch-forming, work-feeding, and other workengaging devices, together with their actuating mechanisms in machines intended for use in the manufacture of Goodyear welt shoes, although in certain of its aspects the invention is readily applicable to locking stitch outseam sewing machines, employing a shuttle instead of loop inserting devices.

The practice in sewing an outseam in Goodyear welt shoes is to employ a lock stitch, shoe outseam sewing machine of the type above referred to, having a curved hook needle and a curved awl acting to engage and penetrate the projecting marginal portions of a welt and an overlying outsole while gripped between a work support and a presser foot inthe machine. The work support is constructed with a substantially horizontal work-gripping surface and has its forward surface ydisposed at an acute angle with the work-gripping surface and concavely curved to fit the bulging last supported portion of the shoe upper, the upper being forced against the concavely curved front surface along certain parts of an outseam to produce a wedging apart action between the welt and the upper, thus enabling the forward edge of the work support to enter fully into a crease formed between the welt and upper without excessive effort on the part of the operator. In this way, the stitches may be inserted in the welt and outsole as closely yas practicable to the crease without otherwise damaging the shoe, the outseam being guided, where required by the line of the crease and the action of the work-gripping and upper engaging surfaces of the work support. While such a clamp and feed arrangement is advantageous in assisting the entry of the work support into the crease between the welt and the bulging upper of a Goodyear welt shoe and in wedging the welt away from the upper to assist in entry of the work support into the crease, the feed movement is intermittent, the work support remaining stationary during the operation of the awl `and needle in forming a stitch. Thus, there is less time available in each sewing cycle for the stitch-forming operation than there would be if the work feed and the stitch-forming operation could be performed simultaneously, and consequently full advantage of the work clamp yand feed action is not obtained.

Intermittent work clamp and feed action of the machine disclosed in the prior application above identiiied is similar to that disclosed in United States Letters Patent No. 2,316,761, granted April 20, 1943, and No. 2,397,588, granted April 2, 1946, both upon application of Fred Ashworth et al., in which machine the feed clamp is secured to a carriage mounted for oscillating movement in an arc of relatively long radius as compared to the circumferential length of the arc through which the feed clamp is oscillated. Prior to the invention of the 2,316,761 patent, it was considered essential to actuate a feed clamp for an outsole stitcher in a horizontal line, even if this line is in the form of an arc centered about a vertical axis. In the machine of the 2,316,761 patent, however, the feed clamp is oscillated through an arc rates aint centered about an axis inclined from the vertical through an angle of substantially less than to the plane of the work-gripping surface of the work support to cause the work support to dip downwardly at the ends of its feeding movement and to move slightly toward the work in a vertical direction during the central section of its feeding movement, thereby assisting in separating the welt from the bulging shoe upper for entry of the work support into the crease and enhancing the clamp and feed action of the work between the work ysupport and presser foot during the central section of the feeding movement. The angle of inclination of the work support oscillating axis is so chosen that the work `support is thrust forwardly and upwardly along the central section of its feeding movement within a plane approximately bisecting the angle formed by the work-gripping and upper-engaging surfaces of the work support. Additional benefits result from the inclination of the oscillating Iaxis by decreasing the frictional forces exerted by the work support on the shoe tending to cause the shoe to move with the work support during its return or back feeding movements, since both the gripping and upper engaging `surfaces of the work support are moved downwardly and rearwardly slightly away from the shoe at the ends of the feeding movement.

An object of the present invention is to obtain still further benefits from such clamp and feed devices and their actuating mechanisms by supplementing the action of the clamp through the use of the needle and awl as additional feed devices while retaining all of the advantages of the prior clamp and feed devices.

A further object of the invention is to simplify and to improve the construction and mode of operation of continuously moving feed devices in a loop lock stitch outsole shoe sewing machine and, incidentally, to organize the other stitch-forming devices and their actuating mechanisms to co-operate with the continuous feed devices more effectively and to an extent not capable of attainment by prior clamp and feed devices.

The principal feature of the present invention resides in a loop lock stitch shoe outseam sewing machine provided with a curved hook needle, a curved awl, a clamp comprising a work support and a presser foot for gripping and feeding the work, and a main sewing shaft for actuating the stitch-forming and work-feeding devices, in which there are mechanisms driven from the sewing shaft for actuating the needle and awl, on the one hand, and the work-gripping clamp on the other hand, to impart a continuous feed movement to the work during a major portion of each sewing cycle, timed to move the clamp in the direction of work feed while imparting a back feed movement to a pin on which the needle and awl are also mounted for oscillation in the line of feed. By such an arrangement the motion of the work is continued during the back feed movement of the feed clamp, in a manner which is particularly advantageous in the use of loop lock stitch forming devices, as distinguished from conventional lock stitch devices utilizing a shuttle.

Other features of the invention certain of which are not limited to use with loop lock stitch forming devices, consist in the devices, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will readily be understood by one skilled in the art from the following `detailed description taken in connection with the -accompanyiug drawings, in which:

FIG. 1 is a perspective view looking from the yfront and left-hand side of the major portion of a machine embodying `features of the present invention;

FIG. 2 is `a similar perspective view on an enlarged scale of the principal stitch-forming and working-engaging devices of the machine shown in FIG. 1;

FIG. 3 is a perspective detail view of a work feed clamp and some of the stitch-forming devices with their actuating mechanisms in the machine;

AFIG. 4 is a detail view in left-side elevation partly broken away and in section of a needle and awl feed carriage together Iwith certain -other stitch-forming and Working-engaging devices. land their .actuating mechanisms;

lFIG. 5 is a detail plan View looking in the direction of vthe arrow V of FIG. 4, showing cla-mp feed and needle and awl feed carriages, together with their AactuatingV mechanisms;

FIG. 6 is aV diagrammatic plan view on an enlarged scale illustrating the manner of obtaining a rearward pull on .the work during feed movements;

FIG. 7 isa fragmentary perspective View on a reduced scale looking from the right front of the machine and showing the feed clamp actuating mechanism;

FIG. 8 is a similar view of the needle and awl feed carriage mechanism;

FIG. 9 is a fragmentary detail View in right side elevation of certain parts in the clamp and needle and awl feed actuating mech-anisms shown in FIG. 5;

FIG. l() is a fragmentary View in elevation of portions of the mechanisms shown in FIG. 9 inpositions assumed during alignment adjustment of the needle and awl in the machine;

FIG. 11 is a perspective detail view, looking from the right front of the machine `and showing an improved looper actuating mechanism;

HHG'. 12 is a view in left-side elevation of an awl actuating mechanism in `the machine;

iFIG. 13 is a fragmentary perspective detail View looking from the left front of the machine and showing loop spreader and cast-off mechanisms, some parts of which are indicated in section;

(FIG. 14 is a detail Iview in left side elevation of portions of the machine partly broken away and in section of needle thread measuring ldevices and their actuating mechanisms;

FIG. 15 is a perspective detail View partly broken away and in section with certain parts shown in separated relation of the needle thread measuring devices and some of their actuating connections;

FIG. i16 is anrenlarged detail view partly in section showing some of the stitch-forming and work-engaging devices in positions assumed during the start of `a new seam in` a shoe;

iFIG. 17 is a detail view in left-side elevation and on avreduced scale of a needle guide and a threaded tension device and their actuating mechanism in the machine;

FIG. 18 is a diagrammatic view including characteristic curves of the Work Iclamp movement while feeding the Work;

FIG. 19 is adiagrammatic View illustrating both forward and rearward movements, and the vertical rise and dip of the work support; and

lFIG. 20 is a time chart illustrating the operation of the various stitch-forming and Work-engaging devices in the machine.

The illustrated machine is equipped with a curved hook needle 2 (see FIGS. 2, 3 and- 4), a curved awl 4, a needle looper 6, ya thread `linger 8, a work clamp comprising a Work support l10 and a presser foot 12, a take-up '14, Iand other stitch-forming, stitch-setting and Work-engaging devices similar to those of the applications and patents above identified, except as hereinafter pointed out. In its general arrangement lthe machine has -a main frame 116 in which are rotatably mounted main and secondary sewing cam shafts 18 and 20 turning in opposite directions and being Vlocated behind `and above the point of operation of the stitch-forming and work-engaging devices, .the sewing shafts being substantially parallel to the line of the seam inserted by. the machine.

The -work is fed in the illustrated machine in part by the movement of a clamp including the Work support and presser foot while gripping the work, as best shown in FIG. 16, and, in part, by movement of lthe needle while engaging the work, the awl 4 acting to form a perforation in the work for the needle while the work clamp is gripping and feeding the Work. During the time that the needle and awl are disengaged from the Work the work is fed by the work clamp alone.

As in the machine of Patent No. 2,316,761, the illustrated machine has other stitch-forming and work-engaging devices for interlocking loops of thread withdrawn from the work with Aa locking thread, for drawing the interlocked needle and locking thread into the work and for setting each stitch. To actuate the stitch-forming and work-engaging devices, the sewing shafts '18 and 20 are provided with cams and other connections by which the movements of the devices are properly timed with rela- -tion 4to each other. lInstead of utilizing a shuttle as in the machine of Patents Nos. 2,316,761 and 2,397,588, the devices for interlocking lthe needle and locking threads in the present machine are .arranged to insert loops of locking thread as in the machine of Patent No. 2,877,725

and application Serial No. 750,392, said loop lock interlocking devices being mounted for movement in the direction of feed together with one of the members of the work clamp.

As in the machine of Patents Nos. 2,316,761 and 2,397,588, both the needle and awl are mounted for oscillation toward and from the work from opposite sides of the work about a single horizontal pin 22, as shown in FIGS. 4 and 5. ln the machine of the prior patents the needle and -awl pin is secured against lengthwise movement on the machine frame and is so arranged that by proper .adjustments the needle and awl are capable of arcuate movement about the axis of the pin and are restrained `from movement lengthwise of the pin to a single plane deiined by the needle and lawl curvatures. In ,this way no diiculty is encountered from misalignment between the needle and awl, so that the needle always enters the perforation formed in the work by .the awl, the work being fed entirely by the clamp while the needle and awl are disengaged from the work.

As in the machine of Patents Nos. 2,316,761 and 2,397,- 58S, the work support 10 is of U shape, a work-gripping surface 26 of which is at the center of the U between a pair of parallel arms. The arms of the work support are screwed to parallel portions of a feed clamp carriage 2S (see FIGS, 3, 4, and 5) rotatable on a pivot shaft 30 inclined rearwardly at an angle substantially less than to a horizontal plane, such as that indicated by a dotdash line 31 in FIG. 4, defined by the work-gripping Surface 26 of the work support. The shaft 30 is secured in enlarged portions of the machine frame 16. The inclination of the shaft 3i) for this purpose is selected at an angle of 60 which will cause a dot-dash line 32 bisecting the angle between the Work-gripping surface 26 and a concave upper gaging surface 34- on the work support (FIG. 4) to intersect the axis, indicated at 36, of the shaft 39 at right angles. The work support during its swinging movement is arranged to exert a thrust along the line 32 toward and from a crease in the shoe formed between the projecting marginal portion of an outsole 37, temporarily attached to a well 38 (see also FIGS. 18a and b), and a bulging last-supported surface of the upper 4t in the shoe, as explained more fully in Patent No. 2,397,588. In its movements along the line 32 toward and from the crease of the shoe, the work-gripping surface 26 dips downwardly and rises to raise the work along the midsect-ion of the clampr feed movement. The gaging surface 34 also moves away from the work slightly at the ends of the feeding movement of the work (FIG. 18a).

Because the gripping pressure exerted on the work by the presser foot is centralized at a point, such as that indicated at 42 in FIG. 6, at the left side of a vertical plane 44 defined by the needle and. awl in the illustrated positions of the parts and represented by a dot-dah line passing through the center of the pivotal mounting shaft 36 at right angles to the line of feed, indicated at 45, the pressure centralizing point 42 moves appreciably rearwardly of the line of feed along an arcuate path 46 by a distance 48 during each feeding movement of the work. The pressure centralizing point 42 never moves to the right side of the plane 44 about which the feed is centered. Since the work is clamped by the work support and presser foot during feed movements, a rearward pull is thus exerted on the work itself. Back feed movement of the work support and presser foot occurs when the foot is raised to release the grip on the work.

During back feed movement the pressure centralizing point 42 of the presser foot moves from the dot-dash position of FIG. 6 to the full line position and fonvardly by the distance 48. ln the full line position of the pressure centralizing point the work is again clamped, so that a rearward pull directed at right angles to the line of feed is continued from one sewing cycle to another, the needle being projected into and holding the work during each back feed movement. The rearward pull of the work support and presser foot on the work has further desirable results in drawing the work into the machine and in causing it to be held in positive contact with an edge gage Sti (FIGS. 2 and 6), which is moved into operative position while the forepart of a shoe is being sewn. While the shank portions of a shoe are being sewn, the edge gage 50 is retracted by the operator and the shoe is guided entirely by the concave upper engaging surface 34 of the work support, it being necessary to insert the seam as closely within the crease as possible while sewing the shank portions of the Shoe. While both features of continued rearward pull by the work clamp and rising action of the work support 1G along the central section of feed with downward dips at the ends of the feeding movement are highly desirable and beneficial as disclosed in the prior patents, these benefits are restricted to a considerable extent by reason of the fact that in the prior machine it is necessary to complete the entire feeding movement within 120 of rotation of the sewing shaft or one-third of the time in each sewing cycle, the work feed clamp being held stationary during the remainder of the cycle when the needle engages the work.

In accordance with an important feature of the present invention, the benefits of the continued rearward pull along the arcuate path 46 on the work and the rising action along the midsection of the clamp feed movement are increased throughout a greater proportion of each sewing cycle to an extent beyond that heretofore considered possible. Except for a matter of 50 wherein the clamp has imparted to it a back feed movement, the remaining 310 or major portion of each sewing shaft rotation in the illustrated machine is taken up by clamp feed movement. Thus, there is a relatively slow feed movement imparted to the clamp throughout a major portion of the sewing cycle followed by a quick back feed movement instead of restricting the clamp feed to a third of each sewing cycle as in prior machines. Also, it has been possible to reduce the radius of the work support carriage arm from 51/2" as in prior machines to approximately 4 in the present machine with more desirable results than in the prior machine. To obtain these advantages without in any way reducing the other desirable features of the machine disclosed in the prior patents or in causing any new undesirable effects, the machine of the present invention utilizes a needle and awl feed mechanism acting together with the feed clamp mechanism to produce a continuous feed movement in the work at constant speed.

The continuous feed mechanisms of the present machine are utilized in connection with loop lockstitch forming devices as distinguished from regular shuttle lockstitch forming devices for interlocking two separate sewing threads, the loop lockstitch depending upon frictional engagement of a loop of locking thread inserted within a loop of needle thread and drawn thereby into the work to set each stitch. In prior loop lockstitch machines it has been necessary to have the work gripped iirmly in stationary position during the formation and setting of stitches in order to prevent the interengaging portions of interlocked loops of thread from enlarging their openings excessively as the threads are drawn into the work. Accordingly, the stitches are embedded firmly and gripped tightly by the surrounding work at the proper positions for a secure seam. To accentuate embedding and gripping the threads in the work, the present work feed devices consist of two separate units driven from the sewing shaft. The needle and awl comprise one unit and the clamp the second unit, both acting in such timed relationship that the clamp moves in the direction of Work feed while a back feed movement is imparted to the needle and awl mounting pin 22 and a clamp and squeeze action of the presser foot and work support prevent excessive displacement of the stitches in the substance of the work during the time of stitch formation and setting. As illustrated, the needle enters the Work just before the feed movement of the clamp takes place and the needle remains in engagement with the work while the clamp is back fed (see FIG. 20). However, the other stitch-forming operations are delayed until the clamp has been back fed and the work again gripped in the clamp. Each stitch is then formed and set during a continued grip of the work support and presser foot on the work while the rising action of the work support increases. In this way, there is no possibility of enlarging the opening into which the thread is drawn in such a manner as to leave the thread loose within the opening after the stitch is set, the gripping action on the work compressing it additionally against the thread to force the walls of the opening firmly into conformity with the threads. These results are further safeguarded in the illustrated machine by providing a separate feed carriage 52 (FIGS. 4 and 5) for the needle and -awl pin 22 arranged for arcuate movement about the same inclined axis 36 of the shaft 30, which serves for the clamp carriage 28. In this way, there is no possibility for excessive enlargement of the stitch-receiving opening by the needle and awl or by other distorting effects being applied to the work during feed, the thread receiving opening in the work alwaysbein'g maintained during feed of the clamp in the same relationship with the plane 44 defined by the needle and awl curvature.

The needle and awl feed carriage 52 comprises a lever having parallel machined faces at its yforward end, to which bearing plates 54 and 56 are screwed. The needle and awl pin 22 about which both the needle and awl are mounted for oscillation toward and from the work, is mounted within bearings in the plates 54 and 56.

The construction of the needle and awl pin 22, and of the bearing in the plates 54 and 56 is similar to that described in United States Letters Patent No. 2,271,611, granted February 3, 1942, upon application of Ashworth et al., the pin 22 corresponding with a pin 464 in the patent and the bearings in the plates being of the same shapes as those in the arms of a fixed bracket 288 in the patent. The construction of the parts surrounding the pin 22 of lthe present machine has been simplified and improved Somewhat from that shown in Patent No. 2,271,- 611 in that a separate two-part driver for the awl, as shown in the patent has been eliminated. Also, a needle guide has been provided having a direct link connection with its actuating mechanism, as will be described hereinafter more fully.

The purpose of the mounting and bearings for the parts surrounding the pin 22, as shown in FIG. 5, is for the purpose of enabling accurate adjustments to be made for alignment of the needle and awl and for causing them to operate in the same plane without looseness between the parts as the result of wear. For this purpose the awl 4 is clamped in a segment 58 formed integrally with the pin 22. The needle 2 is clamped in a segment 60 rotatably supported on a sleeve projecting from the bearing plate 56 and the needle guide, indicated at 61, is mounted for oscillation loosely on the hub of the needle segment 60. The needle segment 60 carries a ball-headed pin 62 surrounded by a socket at the lower end of an actuating link 64.

To restrain movement of the needle and awl lengthwise of the mounting pin 22 and to enable accurate alignment adjustments of the needle and awl in the present machine to bring them into the plane 4.4 at a proper time in a sewing cycle, an arrangement is utilized similar to that of the machine in Patent No. 2,271,611, the needle and awl pin 22 being engaged at opposite ends by screws 66 and 68. The screw 66 is threaded into the bearing plate 54 and the screw 68 is threaded into a sleeve 7d slidably mounted in the bearing plate S6. The sleeve '79 has formed within it a bearing for the left end of the pin 22 and a shoulder on the central portion of the sleeve engages a radial surface formed at the right end of an enlarged opening in the hub lof the needle segment 60 so that as the screw 68 is turned into the sleeve 70 the shoulder of the sleeve is drawn against the needle segment, shifting the pin 22 and the awl segment 58 axially to the right and adjusting the relative positions of the needle and awl. After the screw 68 has been adjusted to bring the needle and awl into the same plane, the set screw 66 acting on the right end of the pin 22 may be adjusted to take up looseness between the parts. To prevent rotation of the sleeve 70, the shoulder on the sleeve has a dat-sided enlargement which tits within a correspondingly shaped recess formed in the needle segment supporting sleeve portion of the bearing plate 56. By .this construction the needle and awl may both be moved in opposite directions and brought into the plane 44 passing through the axis 36 of the shaft 30 and are kept in accurate alignment with each other. Since the alignment of the needle and awl is now insured and the same rearward, rising and dipping movements are imparted to them as are imparted to the work support, there is no possibility of any change in relationship between the needle and awl on one hand and the work support and presser foot on the other hand during overlapping portions of their feeding movements which might disturb the formation of stitches or the handling of the thread, as the result of the inclined relationship of the feed Vcarriage shaft 30. Furthermore, because of the extended time in each sewing cycle during which the work support and presser foot squeeze the work there is a substantial benefit obtained in producing an unusually well-formed seam with the interlocking portions of the thread firmly embedded and symmetrically surrounded by the substance of the shoe outsole.

In order that the operation of the illustrated machine may better be understood, reference may be had to FlG. 18 of the drawings. As indicated at b of this figure, the work consisting of the projecting outsole 37 and welt 38 of the shoe is being subjected to squeeze pressure of the clamp between the work support 10 and the presser foot 12. While each stitch is being formed and setit is highly desirable for the point of interengagement between the needle thread, indicated at 72, and the locking thread, indicated at 74, to be located a definite distance beneath the surface of the outsole 37 without reaching the joint between the outsole 37 'and the welt 38. Also, it is highly desirable that` the size of the opening in the work through which the needle passes be kept as small as possibleand that the substance of the work be molded rmly against the loop of locking thread drawn into the work, the locking loop forming an enlargement about which the outsole is accurately conformed and rigidly compressed. To the extent to which the locking loop is uniformly placed between the surfaces of the outsole, the effectiveness and durability of the seammay vary. With it is possible to maintain a substantial squeeze pressure between the presser foot and work support at a 360 position ofthe sewing shaft 18, releasing the pressure only at a position in a new sewing cycle after the stitch has been uniformly set in the work while in compressed condition. In releasing the squeeze pressure on the work the stitch is correspondingly tightened by expansion of the work and the enlargement at the point of interengagement between the threads is rigidly compressed by the inner surfaces of the recess formed in the sides of the perforation when the enlargement is drawn into the work, etectively preventing movement of the threads one along the other. Furthermore, because of the continued rearward pull exerted by the clamp during its feeding movement, positive guiding action of the edge gage 50 is always maintained without effort on the part of the machine operator or excessive friction between the shoe and the edge gage.

Referring to the curve entitled Clamp Center, it is apparent that from a position of the sewing shaft to a position, the clamp is being back fed and exerts a forward thrust into the crease of the shoe to open up the crease, thus avoiding the necessity for the operator to exert a heavy pressure of the shoe against the forward surface 34 of the work support. Individual fragmentary plan views are located on the chart of FIG. 18 to illustrate the proper relationship of the clamp to the rotation of the sewing shaft. As the sewing shaft reaches a 145 position, the pressure centralizing point 42 (see FIG. 6) about which the clamping pressure is Icentered is moved rearwardly to approximately a half-way position between its rearward and forward locations. During the back feed of the clamp, the position of the needle changes with relation to the work support 10 in the manner indicated in the upper individual fragmentary views of the work support. From the 145 position, the clamp center of the work support moves somewhat forwardly and then rearwardly to its most rearward position at 95 exerting a rearward pull corresponding to the distance between the Start position and the Rearward position on the work.

In case the edge gage is moved rearwardly to an inoperative position, the shoe is guided by the Tip of the Work Support, as indicated in the second curve so entitled. In this case a tip '7S (FIG. 5) of the work support has a forwardly curving front edge and moves equal distances at either side of the plane 44 (FIG. 6) which passes through the axis of the shaft 30. Consequently, the tip of the work support moves rearwardly an amount equal at opposite sides of the plane 44, so that the tip movement does not affect the continued rearward pull exerted about the center point 42 of clamping pressure. The forward movement of the work support tip during clamp return or back feed, however, is relatively short and abrupt so that it assists in opening the crease between the welt and upper. Because the presser foot is raised from engagement with the work as in a and the work support 10 is lowered away from it at the beginning of its back feed movement, as well as being retracted rearwardly, the shoe is readily freed from the grip of the clamp and has practically no tendency to follow the Work support during its back feed or return movement, the presser foot being raised from engagement' with the work between 95 and 155 rotation of the sewing shaft 18. During the remainder of the sewing shaft rotation, the presser foot 12 grips the work against the work support 26 with a squeezing actionexerted gradually and being released gradually in a manner producing the desired results, as illustrated in the third curve entitled Squeeze Action.

Reference to FIG. 19 Will illustrate graphically the type of movement imparted to the work support 10 with relation to a shoe, shown schematically by a dot-dash outline, the axis 36 for the carriage pivot shaft 30 being inclined rearwardly at an angle of 60 to a horizontal plane indicated by the dot-dash line 31. Under these conditions the forward tip edge of the Work support lt) moves forwardly and rearwardly with relation to the shoe by the individual distances between pairs of lines 76 determined by the length of feed movement imparted to the work support in accordance with the adjustment of a hand lever 132 (PEG. l). For a given length of feed movement imparted to the work support lil, as indicated by the locations of the lines 76 at either side of the central point of the feed movement, there will be a corresponding forward and rearward movement indicated by the lengths of the lines 76, the line 45 indicating the direction of feed for a straight seam inserted by the machine under normal operating conditions. Under normal operating conditions the action resulting from the rise and dip of the work support is represented by the parallel lines 77 joining the lines 76 at right angles thereto at either side of the midpoint of the work support lil within its feed movement. During the feed movement the presser foot remains locked in clamping engagement with the work so that as the work support rises and dips the work thickness is compressed and gripped accordingly. Since the forward and rearward movement and the rise and dip of the work support occur together, a particularly advantageous result is obtained entirely independent of the adjustments of feed length or tension imparted to the thread by the needle and locking thread measurement. In this connection it will be noted that the maximum Squeeze Action occurs approximately at a time when the main sewing shaft 1S in the machine has reached a 310 position. lt is at this time that each stitch is being set by the take-up (see FIG. 20). By setting each stitch at a time when the maximum Squeeze Action occurs and thereafter reducing the Squeeze Action, the tension on the thread in a completed seam is enhanced and a maximum holding power is insured. The seam thus produced is formed with tighter stitches than could otherwise possibly be obtained.

To insure that the forces exerted on the work by the work clamp on the one hand and the needle and awl on the other hand will in no manner distort or otherwise displace the work from proper position in the illustrated machine, the carriages 2S and 52 not only swing about the same fixed axis 36 of the shaft 30, but the mechanisms for actuating the carriages are identical in every particular as to length of connections and angular movement, so that a smooth, unvarying feed is obtained throughout the complete sewing cycle.

The feed mechanisms are best shown in FIGS. 4, 5, 7, 8 and 9. As shown in these figures both mechanisms are actuated by a single peripheral groove 78 formed in a cam 80 secured to the sewing shaft 1S. At positions separated by an angle of 180 along the groove '78 above and below the cam are a pair of follower rolls 82 and 84 (FIGS. 7, 8, and 9).

The mechanism for actuating the feed clamp carriage Z8 includes the roll 82 rotatably mounted at the end of an arcuate arm 86 clamped to the upper end of a follower lever shaft 88 arranged parallel to the shaft 30 and rotatable in bearings 9d and 92 formed integrally with the machine frame 16. The arm 86 constitutes a part of a lever and is clamped to the shaft S8 in engagement with the bearing 90. The other arm of the lever comprises a yoke 94 clamped to the shaft and formed with aligned bores in separated portions of its free ends, into which hollow oppositely disposed pivots on a pair of parallel offset bars 96 are litted. Each bar 96 has its pivots spaced the same distance apart as that between the shaft 88 and the free ends of the yoke 94 and both bars together form one member of a pair of toggle links, the other member of which consists of a rod 98, a pivotal connection between which and both bars acts as a knee joint for the toggle links. The knee joint of the toggle links comprises a hollow spacer 160 (see FiG. 9) formed on one of the bars, a rivet 102 passing through the spacer into the other bar 96 and an intermediate bearing portion of the rod 98 within which the spacer lill) is rotatable, the bearing portion of the rod being held between the bars. One end joint of the toggle links 96, 9S consists of a bearing within an enlargement at the opposite end of the rod 93 within which is clamped by a screw 104 threaded into the enlargement, a sleeve lilo having its ends rotatably engaged within aligned openings at a forked end of the feed clamp carriage 28. The other end joint of the toggle links consists of the pivots 95 and the bores at the ends of the yoke 94.

To adjust the feed movement of the clamp carriage the rod 98 projects beyond its intermediate bearing portion through a diametrical opening in a lcylindrical guide block 197 rotatable in spaced portions of a slide M8 mounted on a horizontal track llltl of T-shape cross section secured to the frame l@ of the machine. As the roll 82 is oscillated the yoke 94 swings with the shaft 8S to impart a movement to the feed clamp carriage 28 corresponding to the amount by which the knee joint rivet M2 is displaced from the center of the shaft S8. Accordingly, this displacement of the rivet M2 is directly adjusted by movement of the slide MS on the track llt), the greater the amount of `displacement of the rivet, the greater is the amount of movement imparted to the clamp carriage. To enable the knee joint of the toggle links to swing as close as possible to the shaft S8 the yoke 94 is cut away at 112 (FiG. 7) to receive the knee joint.

The bars 96 and the rod 9S forming the toggle links are of equal lengths between their pivot points and also are of the same length as the distance between the center of the shaft 83 and the end joints of the toggle links between the yoke 94 and the pivots 95. With the equal length arrangement of the toggle links and the distance between the shaft 8S and the end joints of the toggle links the angular movement of the yoke 94 is so selected that the end joints of the toggle links come into alignment and move away from alignment at least once during the movement of the feed clamp carriage ZS during each rotation of the sewing shaft llS. By this movement into and away from alignment of the toggle link end joints identical feeding movements of the needle and awl carriage are kept in co-operative relationship but at different times with identical feed movements of the clamp carriage, in a manner which will be more fully explained hereinafter.

To keep the feed movements of the needle and awl carriage 52 consistently in eo-operative relationship, regardless of adjust-ments, with those of the feed clamp carriage 28, the needle and awl carriage actuating mechanism is made similar to that for the feed clamp carriage and has the lengths of its parts equal throughout to those of the corresponding parts in the feed clamp actuating mechanism. These parts include connections having toggle links, the knee joints of which are movable independently of those in the clamp actuating mechanism and the end joints of which are brought into alignment with each other and with those of the clamp carriage actuating mechanism at least once during each complete rotation of the sewing shaft. By selecting a proper point in the rotation of the sewing shaft at which the end joints of the toggle links in both mechanisms come into alignment with each other at the same time, no variation in relative work feed movements, such as-a faster feed of one than the other, will occur regardless of the adjustments of the mechanisms for actuating both feed carriages. Accordingly, this point, designated as a Focus, defines the transfer of feed movement of the work from the needle and awl unit to the clamp unit with any adjustment of the actuating mechanisms, there being no further engagement of the needle or awl with the work after the clamp starts its feed movement until the next succeeding sewing cycle starts. This Focus point is related to the beginning of the feed clamp movement while the needle is in the work at about the time that the needle withdraws with a loop of thread. As soon as the next succeeding sewing cycle is started, the awl first penetrates the work and forms a perforation for the needle, after which the needle enters the perforation and continues with a feed movement identical in speed to that imparted to the work by the clamp.

The mechanism for actuating the needle and awl feed carriage S2 comprises equal length toggle links in the form of parallel offset bars 114 and a rod 116. One end of the rod 116 has an enlargement provided with an opening, within which is clamped by a screw 11S, a sleeve 120 having its ends engaged within aligned openings in a forked rearward end of the needle and awl carriage 52. The knee joint of the needle and awl toggle links comprises a spacer 122 projecting from one of the bars 114, a rivet 124 passing through the spacer into the other bar 114 and an intermediate bearing portion of the rod 116 within which the spacer 122 is rotatable. One end joint of the toggle links 114, 116 is formed by the sleeve 123 and the rearward end of the needle and awl carriage 52. The other end joint of the toggle links consists of hollow oppositely disposed pivots 126 on the bars 114, which are tted for rotation within aligned bores in separated free ends of a forked arm on a bell crank 12S. The bell crank 12S is rotatable loosely on the shaft 88 and has a second arm forming a support for the cam roll 811.

To adjust the feed movement of the needle and awl carriage, the rod 115 projects beyond its intermediate bearing portion into a diametrieal -opening in a cylindrical guide block 129 rotatable in other spaced portions of the slide 1133, above and in alignment with the block 1l7, all of the dimensions and angular movements of the parts in the needle and awl actuating mechanism being the same as those in the clamp actuating mechanism, thus producing the differently timed identical speed, feed movements in the respective carriages with as much overlap as is possible between the feed movements and with return or back feed movements as short as possible. However, it will be noted in connection with FIG. 20 that the independent needle feed movement occurs only between the ends of the clamp feed movements. Thus, the needle engages the work while the clamp is being back fed and the awl engages the work before the needle. ln the central section of the clamp feed movement, however, throughout a period of more than 180 nothing but the feed clamp engages the work, this section alone of the clamp feed movement being greater than any clamp feed movement obtainable in prior machines.

By providing a Focus point, in which all of the end joints of the toggles 96, 98 and 114, 116 are in alignment, it is possible by makinu all of these joints hollow to pass a pilot pin 131) (FIG. l0) through them for the purposes of holding the parts of the machine stationary, for aligning the needle and awl with respect to the work support and presser foot and otherwise for forming a base position at which the relationship of all of the stitch-forming devices, cams and actuated mechanisms may be checked for properly timed relationship.

For shifting the slide 1li?, .along the track 11i?, the slide is pivotally connected to one end of an adjusting rod 131, as shown in FIG. 7. The other end of the rod is pivotally connected to the hand actuated lever 132, which is mounted at the front of the machine as shown in FlG. l. Movement of the slide 1138 causes the knee joint of both pairs of toggle links in the clamp and the needle and awl carriage actuating mechanisms to be adjusted exactly to the same extent, thus the same relationship of timing between the clamp carriage 2S and the needle and awl carriage 52 is maintained under all conditions. To accommodate the movement in the knee joint of the toggle links 114, 116 for the needle and .awl carriage, the hub of the bell crank 12S is cut away at 133 (FIG. 8) to receive the knee joint.

Certain stitch-forming and work-engaging devices employed in the illustrated machine including the needle looper 6, the thread linger 3, a locking thread carrying finger 134, a locking loop detaining finger 135, a needle loop reti-acting arm 136, a needle loop spreader 13d, a

needle thread feeder 1d@ (FlG. l), a locking thread lock 142, and a locking thread pull-o or controller 144 and their actuating mechanisms are generally similar to those of the machine disclosed in Patent No. 2,877,725, and application Serial No. 750,392. Certain other stitchforming and thread-handling devices, however, in the illustrated machine are actuated by somewhat different mechanisms than disclosed in Patent No. 2,877,725 and application Serial No. 750,392. In the illustrated machine, the needle and awl instead of being actuated by cranks on the shafts 18 and 2) are actuated by pairs of conjugate cams which have peripheral surfaces complemental to each other and engaged by individual cam follower rolls on separate levers, the connections being thereby rendered simpler, lighter and capable of higher speed operation than in the crank-actuated mechanism of the prior patent and application.

Referring to FlG. 4, it will be seen that the link 64 of the needle actuating connections is pivotally suspended at 1415 from a forwardly projecting arm of a lever 146 rotatably mounted on a cam lever fulcrum shaft 148 secured ybetween a pair of plates, one of which is shown at 159, on the machine frame 16. The other arm of the lever 146 supports a cam follower roll 152 engaging the periphery of a cam 154 on the shaft 18. Also rotatably mounted on the shaft 1:18 is a lever 156 carrying on one of its arms a follower roll 158 engaging the periphery of a cam 160. The other arm of the lever 15o is in the form of a relatively thin, integral resilient linger 152 and is engaged at its forward end by an adjusting screw 164, threaded into .a laterally projecting flange on the forward arm of the lever 146, a check nut 166 acting to prevent rotation of the screw 164i after an adjustment has been made. After assembly of the machine the screw 164 may 'ne turned to apply a positive preload to the rolls 152 and 15S and the action of the linger 162 yieldingly takes up inequalities in the peripheries of the cams 154 and 166.

The mechanisms for actuating the awl 4- and the takeup 1d are both of the same general construction as that for actuating the needle. The awl segment 58 has secured to it a ball-headed stud 167 (FIG. 5) surrounded by a socket at the lower end of an actuating link 168, the upper end of which is similarly connected at 170 to a lever 172 rotatably mounted on the shaft 145. The lever 172 is actuated positively by a pair of follower rolls engaging two cams on the shaft 1S in a similar fashion to that in the needle-actuating mechanism, a second cam roll supporting lever 173 rotatably mounted on the shaft 148 being provided with a resilient integral linger 174' engaged by an adjusting screw 176 threaded into a laterally projecting liange of the lever 172 and surrounded by a check nut 17S, as best shown in FIG. 4.

For actuating the take-up 14 (see FIGS. 2 and 14), the take-up is in the form of a right-angle lever rotatable upon a pin 177 secured in a bearing block 179 made fast to the machine frame 16. The take-up has a threadengaging roll 18@ on a downwardly extending arm and on a rearwardly extending arm the take-up lever has pivotally connected to it a link 182, as shown in FIG. i4. The link 152 is also pivotally connected to an upwardly extending arm 184 formed integrally with a rockshaft 186 rotatable in a bearing formed in a block 188 secured to the machine frame. At the opposite side of the block 188 from the arm 134 there is secured to the shaft 186 an upwardly extending arm 190 of shorter length than the arm 184. The upper end of the arm 196* is pivotally connected by a link 192 which, in turn, isV

pivotally connected with a downwardly extending arm of a three-armed lever 194. The lever 194 is rotatably mounted on a horizontal shaft 1% secured at its ends in the machine frame beneath the cam shaft 18. A forwardly extending hooked arm of the lever 194 rotatably supports a roll 19S engaged with the periphery of a cam 2li@ on the sewing shaft 18. Also rotatably 13 mounted on the shaft 196 is a lever 202 having an upstanding arm which supports a roll 204 engaging the periphery of a cam 266, a downwardly extending arm of which lever is perforated to receive a bolt 208 passing through it into an aligned opening in the downwardly extending arm of the lever 194. Within an enlargement of the opening in the arm of the lever 194 is disposed a compression spring 219 acting between the downwardly extending arm of the lever and a washer 212 held in place by a nut 214 on the bolt 2118, which also passes through the spring 216. By means of the spring 21@ a preload is applied to both rolls 196 and 204, so that irregularities in the peripheries of the cams 206 and 206 are taken up by the spring 21).

'Ihe three-armed lever 194 also is connected to actuate a needle thread pull-o arm 216 secured to one end of a shaft 219 (see FIG. 15) in :alignment with a shaft 218. The shaft 219 has connected to it an arm 22() with which the lower end of a link 222 is pivotally connected at 224. The upper end of the link 222 is of reduced width and has a threaded portion secured in an L-shaped block 226 pivotally connected to the rearwardly extending arm of the lever 194. The pull-off arm 216 acts between thread guide portions of a measuring arm 22S secured for rotation with a sleeve 229 surrounding the shaft 219, the sleeve 229 being connected for movement with the presser foot 12.

At opposite sides of the pull-off and measuring arms yalong the path of the needle thread is one of a pair of thread locks, including a guide roll 230 rotatable on a xed shaft 232 and a xed guide block 234, with which co-operate two movable thread gripping shoes 236 and 238. The thread gripping shoes 236 and 23S are supported on two arms of a lever 246 rotatably mounted on a fiXed pin 242 secured in the frame 16 of the machine. The shoes are moved alternately by the lever to grip and release the needle thread 72. The lever 2411 has a toothed arm, the teeth of which engage similar teeth in an arm 244 secured to the shaft 218 which is rotatably mounted in a bearing 246 (FIG. 15) on a plate 24S secured to the machine frame 16.

To actuate the thread locks a mechanism of the same construction is employed, as that disclosed in United States Letters Patent No. 1,519,652, granted December 16, 1924, in the name of Fred Ashworth. In the thread lock actuating mechanism of this patent the shaft corresponding to the shaft 218 has secured to its right end a forked arm similar to that at 249' through the fork of which passes a link, such as shown at 250 surrounded by a pair of compression springs. The present compression springs are shown at 25-1 and provide a yielding connection in two directions between an arm and a link, corresponding to the arm 249 and the link 250. The link 250 is pivotally connected to a downwardly extending arm of a right-angle lever 252 having ia second arm on which is rotatably mounted a roll 254 engaging a groove in a cam on the sewing shaft 18.

The needle loop spreader 13S (FIGS. 2 and 13) is secured in a diametrical bore of a horizontal rockshaft 256 rotatable in the frame 16. Clamped to the rockshaft 256 within a slot formed in a bearing for the shaft is an arm 258, to the free end of which is pivotally connected a link 260. The link 260 has 'a threaded portion surrounded by a pair of check nuts 262 and a compression spring 264, the spring 264 acting against the check nuts and a portion of the machine frame 16 through which the link 260 passes. The other end of the link 260 is pivotally connected to a lever 266 fulcrumed on `a pin 268 and provided with a roll 270 engaging the periphery of a cam 272 on the sewing shaft 20. The spring 264 maintains the roll 276 in 1engagement with the cam 272 and insures proper lactuation of the loop spreader.

The needle loop retracting arm 136 in the illustrated machine is actuated independently of the loop spreader 13S. As shown in FlG. 13 the retracting arm 136 is 14 secured to a block 274 clamped to a shaft 276 rotatable in bearings in the machine frame 16. At the rearward end of the shaft 276 is fixed an arm 278` having a roll 280 engaged within a circumferential groove in a cam 282 on the sewing shaft 20.

The mechanism for actuating the locking thread carrying Yfinger 134 in the illustrated machine is similar to that employed for actuating the loop spreader 13S. The locking thread carrying finger 134 is mounted on a carrier connected for movement with the presser foot and is arranged to enter each loop of needle thread from within the arc of curvature of the needle 2, so that it does not project ohjectionably beyond the front of the machine. As shown in FIG. 3 the thread carrying finger 134 is secured to the lower end of an arm 284 mounted for swinging movement about a pin 286 passing through the forward end of an arm 288 forming the carrier. The rearward end of the carrier arm 266 is secured to -a shaft 290 rotatable in -a bearing on the work support carri-age 2S. Near its forward end the arm 28S has an opening fitting a dowel 292 secured in the forward end of a presser foot lever 294. The presser foot lever 294 has attached to it the presser foot 12 and at its rearward end the lever is forked to straddle a portion of the feed carriage 2S through which and the presser foot lever there projects a fulcrum pin 296 aligned with the shaft 290 of the carrier for the thread carrying finger. The arrangement is such that the thread carrying finger 134 rises and falls with the presser foot 12, as in the machine of application Serial No. 750,392. The arm 284 is connected through a link 298 to a lever 300 rotatable at the lower end of an inclined pin 302 clamped at its upper end in the carrier arm 28S. Also pivotally connected to the lever 34N) is a link 3114 pivotally connected to the lower end of a cam lever 3116. The cam lever 3116 is fulcrumed on a pin 3113 (see FIGS. 2 and 3) mounted in a lug on the main frame 16 of the machine. At the upper end of the lever 306 there is mounted a roll 309 (FIG. 3) engaging the periphery of a cam 311B secured to the sewing shaft 2i). Also engaging the upper end of the lever 306 is a cylindrical block 312 slidingly mounted in the machine frame and acted upon by a compression spring 3114, the other end of which is backed by the main frame, the spring maintaining the roll 368 in engagement with the cam 310.

The locking Iloop detaining finger 135 is mounted in the end of a rod 316 (FIG. 3) secured within a split clamp 317 at the end of a bar 318, which in turn is similarly secured on an larm 320 clamped to a shaft 322 rotatably mounted in the presser foot lever 294. Formed integrally with the shaft 322 is an arm 324 pivotally connected to a link 326 of the detaining finger actuating mechanism. This mechanism is similar to that disclosed in Patent No. 2,877,725.

For actuating the locking thread lock 142 and the locking thread pull-off 144, these devices are connected with mechanism for actuating the needle guide 61. This mechanism is best shown in FIGS. 2 and 17 and comprises a link 327 connected by universal joints between the needle guide and a downwardly curved arm of a cam lever 328 fulcrumed ion a shaft 33t) and provided at its rearward end with a follower or roll 332. The roll 332 engages a groove 334 in a cam 336 secured to the sewing shaft 18. The lever 328 also has fixed to it an arm 337 pivotally connected to a link 33S extending to a similar connection with an arm 340 secured to a pin 342 rotatably mounted in the machine frame 16. Also secured to the pin 342 is an arm 344 arranged to engage the rearward end of a threaded stud 346 passing loosely through an opening in the frame 16 and a pair of thread-engaging disks 348 between which the locking thread passes. Surrounding the rearward threaded end of the stud 346 is a compression spring 349 and a thumb nut 350 which cause the disks to be brought against the thread passing between them to lock the thread against movement at certain 

